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Showing 1 to 20 of 20 for “"Tufa"”.
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Tufa-based reconstructions of Huasco Basin Lake levels
… region. To create this lake level chronology, tufa samples deposited at different elevations within the Salar del Huasco were dated using U/Th disequilibrium dating, and stable isotope measurements were applied to examine the past hydrology of the basin. The Salar del Huasco was found to have …
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Environmental and climatic aspects of the early to mid Holocene calcareous tufa and land mollusc fauna in southern Sweden
… deposition of freshwater calcium carbonates, tufa, has occurred in large areas with carbonate soil or bedrock in Sweden, no tufa formation has been observed in Sweden. To better understand the factors controlling tufa formation in southern Sweden, bio- and lithostratigraphical studies were …
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An investigation of the tufa deposits at Ga-Mohana Hill in the Northern Cape, South Africa: palaeoenvironmental context for Late pleistocene and holocene human occupation in the Southern Kalahari
… Secondary calcium carbonates, including tufa, are common in the Kalahari, yet their palaeoclimate potential remains relatively unexploited. Tufa deposits at Ga-Mohana Hill, an archaeological site in the southern Kalahari, represent past water availability in a presently semi-arid region. …
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Depositional constraints on lacustrine carbonates from the Winnemucca Dry Lake Basin, Nevada, USA
… of lacustrine carbonate rocks, known as “tufas”, are exposed along the margins of Pyramid Lake and Winnemucca Dry Lake, adjacent lake basins located in the Basin and Range Province of western Nevada (USA). Tufas are in-situ accretionary carbonate deposits that build upward from the lake …
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Age, Stratigraphy and Depositional Environment of the Pliocene Copper Canyon Formation, Death Valley, California
… saline lake, and perennial fresh to saline lake. Tufa mounds reflecting active spring deposition are numerous within the upper two-thirds of the formation. Stable isotope data (δ18O ranges from -10.15 to -10.96‰ PDB) from the tufa mounds indicate the lake was fed by relatively fresh groundwater. …
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Characterization of Ulva (Ulvaceae, Chlorophyta) species cultured in commercial abalone farms in South Africa, and comparison with closely related wild species, using morpho-anatomical and molecular methods
… DNA (ITS nrDNA) and the elongation factor tufA. The 12 cultured Ulva specimens belonged in the U. lacinulata clade with weak support value of 0.57 for PP in the rbcL tree, high support value of 0.86 for PP in the ITS tree and high support value of 92% and 0.92 for BP and PP, respectively, …
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A Conceptual Model of Groundwater Flow at the Midway, Utah Fish Hatchery as Constrained by Geochemical, Physical Hydrogeological, and Geophysical Methods
… log profile for the site shows discontinuous tufa layers amid heterogeneous alluvium material. These tufa layers separate upward leaking confined aquifers from the unconfined system. It is only through the integration of several methods that such mixed systems, can be understood. In this …
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Surface Offset and Slip Rates for the Winter Rim Fault System in the Summer Lake Basin, Oregon
… with fault scarps that cut radiocarbon-dateable tufa-coated paleoshorelines from Pleistocene Pluvial Lake Chewaucan. The faults have been active since the lake receded, and paleoshorelines are offset and no longer continuous. Twenty-four shoreline tufa samples were measured and calibrated, …
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Contribution of Recharge Along Regional Flow Paths to Discharge at Ash Meadows, Nevada
… under the current stress field, and the buried tufa mounds (revealed with ground penetrating radar data) indicate localized upwelling from a deeper regional water source.
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Evolution of early Proterozoic passive-margin carbonate platform, Rocknest Formation, Wopmay Orogen, N.W.T., Canada
… facies are shallowing-upward cycles of tufa, cryptalgalaminite, laminated dolosiltite/lutite, overlain by tepees, breccias and pisolite; these formed a paleotopographic high, restricting an eastern "lagoon" from western ocean. Innershelf facies are dominantly asymmetric, …
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U-Th Dating of lacustrine carbonates
… lacustrine carbonates: lake bottom sediments and tufa deposits. Chapter 2 presents a systematic approach to U-Th dating carbonate-rich lake sediments using the ICDP sediment core from Lake Junín, Peru. Chapters 3–5 seek to demonstrate the descriptive power of combining precise U-Th dates on tufas …
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Questions and clarity: insights from applying computational methods to paleoclimate archives
… This work is able to connect facies in the tufa at Searles, grown during the Last Glacial Period, and those forming presently at Mono Lake. Next, the tracks of icebergs purged during Heinrich Events are simulated using the MIT General Circulation Model. This work, running multiple …
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Questions and Clarity: Insights from Applying Computational Methods to Paleoclimate Archives
… This work is able to connect facies in the tufa at Searles, grown during the Last Glacial Period, and those forming presently at Mono Lake. Next, the tracks of icebergs purged during Heinrich Events are simulated using the MIT General Circulation Model. This work, running multiple …
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Media coverage, industrial policy, and safety : explaining shifting state and Private ownership in China's coal-mining industry
… turned accidents into "sudden incidents" (tufa shijian) perceived to threaten social stability and state legitimacy. This media-generated pressure was reinforced by the disciplinary apparatus, which was itself responsive to media coverage and accident patterns. A subset of coal provinces …
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Geochemical records in travertine veins at the Green River CO2 seeps (Utah)
… fluid compositions from 100m to 10km scales. Tufa/travertine (CaCO3) deposits form at modern springs, and historic deposits form along both faults. Fossil travertine veins can be dated by U-Th chronology and preserve chemical signatures of the fluids they form from: trace metals, δ234Ui and …
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Cenozoic Sedimentary Evolution of the Helmville Basin, West-Central Montana
… but is locally exposed. The presence of aligned tufa mounds within the central part of the basin suggests the presence of at least one additional en echelon fault.</p>
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Cenozoic Sedimentary Evolution of the Helmville Basin, West-Central Montana
… but is locally exposed. The presence of aligned tufa mounds within the central part of the basin suggests the presence of at least one additional en echelon fault.</p>
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The use of ecological studies, genetic tools, and citizen science to asses the biological invasion status of green seaweed Codium fragile (Suringar) Hariot 1890 in the southern area of the Bay of Biscay (Cantabrian Sea)
… y C. vermilara utilizando las secuencias tufA y rbcL. Se encontraron niveles bajas de variación genética poblacional para las especies de Codium nativas / invasoras examinadas, lo que sugiere mecanismos sexuales y de propagación similares para todas las especies. El marcador FCOtufA de …